Get vertices from Edge list

I have a large dataset with about 20,000 edges. I prepared data by "getting vertices from the edge list" after messing around with it for a long time I realized some vertices hadn't been created. So I hit get vertices... again but nothing changed.
Then I deleted all vertices and tried getting vertices, but while the network exists. the vertices page still does not have any vertices in the vertex column. How can i recreate the vertices from the edgelist?

Let's take the original problem first. NodeXL, Data, Prepare Data, Get Vertices from Edge List copies every unique vertex listed in the Edges worksheet to the Vertices worksheet. If you notice afterward that a vertex is missing from the Vertices
worksheet, it might be because it simply does not exist in the Edges worksheet. Another possibility is that there is an empty row in the Edges worksheet that is causing succeeding rows to be excluded from the Excel table that NodeXL considers to be the
"boundary" of the edge list. The Excel table is distinguishable from the rest of the worksheet by the colored cell backgrounds in the table rows.

On to the second problem: My bet is that when you deleted the vertices, you accidentally corrupted the Vertices worksheet. Your best bet is to just start from scratch by copying your edge list into a new NodeXL workbook.

I did start from scratch and redo the worksheet and it works fine now. But being persnickety I kept messing around with the other file and it was indeed creating the vertex list but below row 10,000 (earlier i had about 10,000 rows in the vertex list). So
when i deleted all vertices perhaps it did not register the deleted rows as being blank, probably because it still had some undeleted colum graph metric column for the deleted vertices.

By the way, NodeXL will automatically fill in the Vertices worksheet for you when you show the graph using NodeXL, Graph, Show Graph. You need to use Get Vertices from Edge List only if you want to set some vertex attributes on the Vertices worksheet
before showing the graph.